Research On Enhanced Physical Downlink Control Channel(EPDCCH) In LTE-A System

With the continuous evolution of the 3GPP standard, the demand for data transmission in the wireless network environment is also growing rapidly. In LTE-A system, the introduction of heterogeneous network scenarios and the use of CoMP, ICIC, CA and other technologies make the demand for control signaling surge. The capacity of the downlink control channel becomes one of the significant bottlenecks that affect system performance. Therefore, 3GPP first proposes EPDCCH in R11 to address thecapacity problem caused by growing signaling. EPDCCH does not occupy the resources of the PDCCH control domain, but carries on the transmission in the PDSCH partial bandwidth through frequency division multiplexing with the PDSCH data domain.At the same time, in order to coordinate the channel resources, 3GPP specifies theEPDCCH physical resource block that does not occupied will be used to transmit UE data. Therefore, how to effectively allocate the resources through the EPDCCH search space and improve the efficiency of blind detection is urgently needed to solve.Firstly, this thesis deeply studies the LTE-A physical layer protocol and briefly introduces the physical layer processing flow, frame structure and resource grid, then focuses on the analysis of the resource structure, transmission mode, transmission and reception process ofEPDCCH.For EPDCCH search space resource allocation algorithm, the thesis first introduces the EPDCCH semi static search space resource allocation algorithm and dynamic search space resource allocation algorithm, and analyses the resource utilization and blocking rate of the two algorithms in detail. In view of the existing problems, the thesis proposes an improved algorithm based on dynamic search space resource allocation. The improved algorithm inherits the characteristics of dynamic search space resource allocation algorithm. At the same time, through the candidate of the continuous EPDCCH set discretization to partition a subset of the resources, it reduces the system blocking rate and improves the resource utilization rate. Finally, through the simulation analysis, the improved algorithm has a certain degree of promotion than the existing performance better dynamic search space resource allocation algorithm in resource utilization, reaching the maximum of 8%, and in the blocking rate, the maximum decrease of 70%.Search space is to simplify the complexity of blind detection. For EPDCCH blind detection algorithm, the thesis first analyses the both realization method and existing problems of exhaustive blind detection algorithm and adaptive blind detection algorithm. Concerning on that adaptive blind detection algorithm is difficult to maintain performance in complex channel environment, the thesis proposes an improved algorithm based on adaptive blind detection. The improved algorithm can effectively avoid the influence of complex channel by calculating the SINR of CQI to get the first aggregation level of UE. Finally, through the simulation analysis,the number of the improved algorithm of blind detection significantly reduces in the same environment.